Photoluminescence and band gap modulation in graphene oxide

Abstract

We report broadband visible photoluminescence from solid graphene oxide, and modifications of the emission spectrum by progressive chemical reduction. The data suggest a gapping of the two-dimensional electronic system by removal of π-electrons. We discuss possible gapping mechanisms, and propose that a Kekule pattern of bond distortions may account for the observed behavior.

Graphene photonics and optoelectronics

“…Even though some groups assigned PL in GO to bandgap emission from electron confined sp 2 islands [17][18][19] , this is more likely to arise from oxygen related defect states 16 . Whatever the origin, fluorescent organic compounds are of significant importance to the development of low-cost opto-electronic devices 28 .…”

“…Even though graphene nanoribbons (GNRs) have been produced, with varying band gaps 7 , to date no photoluminescence (PL) has been reported from them. However, bulk graphene oxide (GO) dispersions and solids do show a broad PL [17][18][19]27 . Individual graphene flakes can be made brightly luminescent by mild oxygen plasma treatment 16 .…”

“…This combination of photoluminescent and conductive layers could be used in sandwich light-emitting diodes. Luminescent graphene-based materials can now be routinely produced covering the infrared (IR), visible and blue spectral range [16][17][18][19]27 .…”

“…Saturable absorption is observed as a consequence of Pauli blocking 13,14 , non equilibrium carriers result in hot luminescence 15 . Chemical and physical treatments also enable photoluminescence [16][17][18][19] . These properties make it an ideal photonic and optoelectronic material.…”

Making Graphene Luminescent by Oxygen Plasma Treatment

“…16 Bulk GO solutions and solids do also show a broad luminescence background. 17,18 Hydrogen plasma was used to controllably and reversibly modulate the electronic properties of individual graphene flakes, turning them into insulators. 15 Aggressive oxygen treatment was applied to create graphene islands.…”